A wind motor is a power conversion device which derives its power from the wind. Wind motors possess the unique advantages of using a power source which is both free and inexhaustible.
Conventional wind motors utilize a propeller type rotor placed in an ambient airstream to convert the energy of the airstream into rotary mechanical power. The mechanical power thus derived can be used for various purposes including driving an electric generator.
In order to generate large amounts of power, it is necessary that a wind motor have a large area exposed to the wind. Unfortunately, propeller driven wind motors become extremely impractical at relatively large sizes. For example, in order to increase the size and exposed area of a propeller wind motor, it is necessary to increase the diameter of the propeller, and before a large enough diameter to produce substantial power is reached, the cost and expense problems associated with the large propeller and its mounting structure become limiting factors. These size and cost factors are magnified if the propeller is to be used within a diffuser.
As the diameter of the propeller is increased, the maximum speed of rotation must be reduced. However, with a propeller driven wind motor, the maximum speed of rotation must be reduced rather sharply as the diameter of the propeller is increased. In addition, a propeller produces air swirls downstream of the propeller which create energy losses.